Compared with petrochemical, industrial, electric power and other pipe networks, the central heating pipe network has its own characteristics and requirements for valves:
1) Different from industrial process valves, the valve is normally open most of the time when the heating pipe network is running normally, and the valve needs to be closed under special requirements or emergency circumstances. Therefore, the valve is required to have stable performance and excellent structure, so as to ensure that good sealing performance can be achieved when needed. Otherwise, it will not be possible to carry out follow-up emergency repairs or construction, which will lead to serious problems and cause huge economic losses and social impacts.
2) There are many impurities in the heating pipe network, which is a well-known thorny problem in the entire industry. This requires that the sealing pair of the valve has sufficient strength, hardness and reasonable structure to make it not affected by water flow and impurities washing and clamping pressure when closing.
The heating pipe network is mostly laid underground, and the valve is installed in the valve well with limited space, which brings a lot of inconvenience to the maintenance and replacement of the valve. Therefore, the valves of the heating pipe network are required to have the characteristics of long life and maintenance-free to reduce the workload of maintenance and replacement.
The temperature difference between the operation and non-operation of the heating pipe network is large, and the thermal stress generated by the pipeline is also very large. With the widespread use of uncompensated direct buried pipe networks, this problem has become particularly prominent. This requires that the valve should be able to operate normally within a large temperature difference, with a solid structure, dense processing, and can withstand sufficient stress The upstream and downstream shutdown of the valve in the pipeline network during emergency maintenance may need to withstand the medium pressure in different directions, which requires the valve to achieve two-way sealing performance of the same grade.
With the application of multi-heat source networking system, the pressure of each heat source in the network may be different, in order to achieve effective and reasonable distribution and control of heat source, the two-way sealing performance of the valve is particularly important.
Due to the limitation of installation and operation space, the weight and volume of heating pipe network valves are also limited. Considering the safety factors of electricity consumption, most heating pipe network valves basically cannot use electric actuators, so the operating torque of the valve must be small.